Simultaneous Determination of Six Major Constituents in the Stems of Kadsura heteroclita by LC-DAD

The stem of Kadsura heteroclita is a traditional Chinese medicine with a variety of biological activities. For efficient monitoring of the quality of the herb, a simple, rapid, and accurate HPLC method has been developed for simultaneous determination of five cyclolanostane triterpenoid compounds (schisanlactone E, nigranoic acid, schisandronic acid, and heteroclitalactones A and D) and one tetrahydrofuran lignan (d-epigalbacin) in the stems of K. heteroclita. These six compounds were separated on a C₁₈ column by elution with a mobile-phase gradient prepared from acetonitrile and 0.05% (v/v) aqueous phosphoric acid. The flow rate was 1.0 mL min⁻¹ and the detection wavelength was 210 nm. The recovery of the method was in the range 95.03–102.19% and a good linear relationship (r ² > 0.9999) was obtained between response and compound concentration over a relatively wide range. The method was successfully applied to analysis of the herb collected at different stages of growth.     

Simultaneous RP-LC Determination of Ketorolac and its Piperazinylalkyl Ester Prodrugs

A simple, rapid and selective RP-HPLC method was developed and validated for the determination of ketorolac and five piperazinylalkyl ester prodrugs. A binary isocratic mobile phase composed of a mixture of 65:35 (v/v) 0.02 M phosphate buffer (pH 5.4) and acetonitrile was used on a C₁₈ column (125 × 4 mm, 5 μm). The injection volume was 25 μL and the detection wavelength was 314 nm and the flow rate was 1.5 mL min⁻¹. The method exhibited excellent linearity with R ² of no less than 0.999 and intra-assay and inter-assay precision that were less than the maximum amount allowed according to Horwitz equation. The accuracy was found to be within the allowed ±15%. The limits of detection for the analytes were between 0.060 and 0.220 μg mL⁻¹ and the limits of quantification were between 0.183 and 0.667 μg mL⁻¹. This method was used successfully for the study of the solubility, stability and partition coefficients of piperazinylalkyl ester prodrugs of ketorolac.     

Validated LC Method, with a Chiral Mobile Phase, for Separation of the Isomers of Fexofenadine Hydrochloride

A rapid, simple and sensitive high-performance liquid chromatographic method (HPLC) has been developed to assay atomoxetine HCl in capsules. The HPLC analysis used a reversed phase C18 (150 × 4.6 mm i.d. 5 μm particle size) analytical column and a mobile phase consisting of monobasic potassium dihydrogen orthophosphate and acetonitrile (95:5 v/v), with UV detection at 269 nm. The validation data showed that the assay is sensitive, specific and reproducible for determination of atomoxetine HCl in this dosage form. Calibration curves were linear from 1 to 10 μg mL⁻¹ (R ² > 0.997). The accuracy of the method ranged from 98.13 to 101.5%. Mean inter- and intra-assay relative standard deviations (RSD) were less than 1.0%. The proposed method provided an accurate and precise analysis of atomoxetine HCl in its pharmaceutical dosage form.     

Quantitative HPLC Determination and Stability Studies of Pyridostemin in Extracts and Water Dispersible Granule Formulations of Stemona curtisii

A reversed-phase high-performance liquid chromatographic method has been developed and validated for the determination of pyridostemin, the major pesticidal alkaloid found in Stemona curtisii. This methodology was applied to the investigation of plant extracts and water dispersible granule formulations. Stability indicating procedures have also been carried out. The chromatographic separation was on a C₁₈ column with a mixture of acetonitrile–water–triethylamine (30:70:0.12, v/v/v), using UV detection at 300 nm. Validation procedures showed that the method was specific, accurate and precise. The response was linear over a range of 5–25 μg mL⁻¹ with recoveries in the range of 98.28–102.85%. The RSD for intra- and inter-day precision were <0.72 and <1.29%, respectively. Extraction of plant material with dichloromethane gave a significantly higher pyridostemin content in the crude extracts when compared with extractions in methanol. Partial purification of the crude extracts by silica gel column chromatography was used to concentrate the mixture about fourfold. Degradation behavior of pyridostemin in the partially purified extracts followed first-order kinetics. The main pathways for its decomposition were base hydrolysis and oxidation.     

Development and Validation of a Stability-Indicating LC Method for Determination of Ebastine in Tablet and Syrup

A simple stability-indicating reversed-phase liquid chromatographic method with diode-array detection was developed and validated for the quantitative determination of ebastine in tablets and syrup. The LC method was carried out on a C₁₈ column with acetonitrile:phosphoric acid 0.1% pH 3.0 (55:45, v/v) as mobile phase, at a flow rate of 1.2 mL min⁻¹. Ultraviolet detection of ebastine was at 254 nm. A linear response (r = 0.9999) was observed in the range of 10–80 μg mL⁻¹. The RSD values for intra- and inter-day precision studies showed good results (RSD < 2%) and accuracy was greater than 98%. Validation parameters such as specificity and robustness were also determined. The method was found to be stability-indicating and can be applied to quantitative determination of ebastine in tablets and syrup.     

Development of a Validated Stability-Indicating LC Method for Nitazoxanide in Pharmaceutical Formulations

A reversed-phase liquid chromatographic (LC) method was developed for the assay of nitazoxanide (NTZ) in solid dosage formulations. An isocratic LC separation was performed on a Phenomenex Synergi Fusion C₁₈ column (250 mm × 4.6 mm, i.d., 4 μm particle size) using a mobile phase of 0.1% o-phosphoric acid solution, pH 6.0: acetonitrile (45:55, v/v) at a flow rate of 1.0 mL min⁻¹. Detection was achieved with a photodiode array detector at 240 nm. The detector response for NTZ was linear over the concentration range from 2 to 100 μg mL⁻¹ (r = 0.9999). The specificity and stability-indicating capability of the method were proved using stress conditions. The RSD values for intra-day precision were less than 1.0% for tablets and powder for oral suspension. The RSD values for inter-day precision were 0.6 and 0.7% for tablets and powder for oral suspension. The accuracy was 100.4% (RSD = 1.8%) for tablets and 100.9% (RSD = 0.3%) for powder for oral suspension. The limits of quantitation and detection were 0.4 and 0.1 μg mL⁻¹. There was no interference of the excipients on the determination of the active pharmaceutical ingredient. The proposed method was precise, accurate, specific, and sensitive. It can be applied to the quantitative determination of drug in tablets and powder for oral suspension.     

Development and Validation of LC–MS Method for the Determination of Hydroxyzine Hydrochloride in Human Plasma and Subsequent Application in a Bioequivalence Study

A rapid, simple and specific liquid chromatography-electrospray ionization mass spectrometry method has been developed and validated for the determination of hydroxyzine hydrochloride in human plasma. Samples were separated using a Thermo Hypersil-HyPURITYC18 reversed-phase column (150 mm × 2.1 mm i.d., 5 μm). The mobile phase consisted of 50 mM ammonium acetate (pH 4.0)–methanol–acetonitrile (45:36:19, v/v). Hydroxyzine and its internal standard were measured by electrospray ion source in positive selective ion monitoring mode. The method was validated with a linear range of 1.56–200.0 ng mL⁻¹ and the lowest limit of quantification was 1.56 ng mL⁻¹ for hydroxyzine hydrochloride (r ²= 0.9991). The extraction efficiencies were about 70% and recoveries of the method were in the range of 93.5–104.4%. The intra-day relative standard deviation (RSD) was less than 8.0% and inter-day RSD was within 7.4%. QC samples were stable when kept at ambient temperature for 12 h at −20 °C for 30 days and after four freeze–thaw cycles. The method has been successfully applied to the evaluation of pharmacokinetics and bioequivalence of two hydroxyzine hydrochloride formulations in 12 healthy Chinese volunteers after an oral dose of 25 mg.     

Quantification of cis-Abienol in Oriental Tobacco Leaves by LC

A rapid and accurate method for the quantification of cis-abienol in oriental tobacco leaves by normal phase liquid chromatography was developed. Freeze-dried tobacco samples were sonicated in methylene chloride for 10 min. The supernatant was purified using a silica gel solid phase extraction cartridge. Ten milliliter of the resulting methylene chloride eluate was collected, then separated on a 250 × 4.6 mm, 5 μm particle-size CN column with n-hexane: ethyl acetate, 100:2 (v/v) at a flow rate of 1 mL min⁻¹. cis-Abienol was detected by UV absorption at 254 nm. The linear range was from 2.14 × 10⁻⁴ to 4.28 × 10⁻² mg mL⁻¹ and the correlation coefficient was 1.000. The average recovery was 98.7, 105.2 and 103.1% in five replicated sets of tobacco samples spiked with 0.2856, 0.7140 and 1.904 mg cis-abienol. The relative standard deviations (RSDs) were 1.04, 0.63 and 1.25%, respectively (n = 5). Limit of detection (S/N = 3) was 21.84 μg g⁻¹ and limit of quantification (S/N = 10) was 72.80 μg g⁻¹. The method was found to be suitable for determination of cis-abienol in oriental tobacco leaves. Furthermore, pure cis-abienol used for method validation was obtained by preparative reversed phase high-performance liquid chromatography. Identification was performed by UV detection, nuclear magnetic resonance and mass spectrometry.     

Isolation and Simultaneous Determination of Coumarin Compounds in Radix Angelica dahurica

For the first time simple, rapid, and systematic methods have been established for preparative isolation and purification of coumarin compounds in an important traditional Chinese Medicine, Radix Angelica dahurica, and for simultaneous determination of several of the compounds in the medicine. Bergapten, imperatorin, and cnidilin, three of the biologically active coumarin compounds, were isolated from the chloroform-soluble fraction of the ethanol extract of Radix Angelica dahurica. After further purification by open column ODS chromatography the purified components were simultaneously determined, with two other coumarins (osthole and isoimperatorin), by reversed phase high-performance liquid chromatography (RP-HPLC) on a C₁₈ column, with methanol–water, 66:34 (v/v), as mobile phase at a flow rate of 0.8 mL min⁻¹. The compounds were detected by UV absorption at 310 nm. Calibration plots for all the coumarins had correlation coefficients close to unity. Limits of detection (S/N = 3) were <92 ng mL⁻¹ and limits of quantification (S/N = 10) were <259 ng mL⁻¹. Mean recovery of the coumarins was in the range 96.7–101.9% and the intra-day and inter-day precision, as relative standard deviation, was <2.3 and <2.9%, respectively. This simple, sensitive, and reproducible method can be used for quality control of Radix Angelica dahurica.     

Simultaneous Determination of Enalapril and Enalaprilat in Human Plasma by LC-MS: Application to a Bioequivalence Study

A rapid, simple and specific liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) method has been developed and validated for the simultaneous determination of enalapril and its major active metabolite enalaprilat in human plasma. Benazepril hydrochloride was used as the internal standard. Plasma was deproteinized with acetone and centrifuged. The supernatant was transferred and evaporated to dryness and the residue dissolved in mobile phase. Samples were separated on a C18 column with a mobile phase of methanol–20 mM ammonium acetate (53:47, v/v) containing 0.15% trifluoracetic acid (v/v) with a pH of 3.0. Enalapril, enalaprilat and the internal standard were measured by electrospray positive selective ion monitoring mode. The method was validated over a linear range of 1.56–400 ng mL⁻¹ and the limits of quantification were 1.56 ng mL⁻¹ for both enalapril and enalaprilat using 0.1 mL plasma. Extraction efficiency was more than 84% and recoveries were in range of 93.65–101.17%. The intra-day relative standard deviations (RSD) were less than 8.16 and 7.05% and inter-day RSDs were within 8.42 and 5.72% for enalapril and enalaprilat, respectively. The storage stability of QC samples was investigated under various conditions. The method was successfully applied for the evaluation of the pharmacokinetics and bioequivalence of enalapril and enalaprilat in 20 healthy volunteers after an oral dose of 20 mg enalapril maleate.     

Analysis of isoflavones and flavonoids in human urine by UHPLC

A rapid, ultra high-performance liquid chromatographic (UHPLC) method has been developed and validated for simultaneous identification and analysis of the isoflavones genistein, daidzein, glycitin, puerarin, and biochanin A, and the flavonoids (±)-catechin, (−)-epicatechin, rutin, hesperidin, neohesperidin, quercitrin, and hesperetin in human urine. Urine samples were incubated with β-glucuronidase/sulfatase. UHPLC was performed with a Hypersil Gold (50 × 2.1 mm, 1.9 μm) analytical column. Elution was with a gradient prepared from aqueous trifluoroacetic acid (0.05%) and acetonitrile. UV detection was performed at 254 and 280 nm. The calibration curves were indicative of good linearity (r ² ≥ 0.9992) in the range of interest for each analyte. LODs ranged between 15.4 and 107.0 ng mL⁻¹ and 3.9 and 20.4 ng mL⁻¹ for flavonoids and isoflavones, respectively. Intra-day and inter-day precision (C.V., %) was less than 3.9% and 3.8%, respectively, and accuracy was between 0.03% and 5.0%. Recovery was 70.35–96.58%. The method is very rapid, simple, and reliable, and suitable for pharmacokinetic analysis. It can be routinely used for simultaneous determination of these five isoflavones and seven flavonoids in human urine. The method can also be applied to studies after administration of pharmaceutical preparations containing isoflavones and flavonoids to humans.     

LC Determination of Gemfibrozil in Tablets

A simple, selective, precise and accurate reversed phase-HPLC assay for analysis of gemfibrozil in tablets was developed and validated. Separation and quantification were achieved on a Phenomenex C₁₈ column under isocratic conditions using a mobile phase (methanol:water, 80:20, v/v) maintained at 1.1 mL min⁻¹. UV-detection was at 280 nm. Atorvastatin was selected as an internal standard. The standard curves were linear over the range of 0.5–3.0 μg mL⁻¹ (r > 0.999). The limits of detection and quantification were 0.20 and 0.51 μg mL⁻¹, respectively. The recoveries for gemfibrozil were above 99.01%. The intra-day and inter-day precision (RSD) for gemfibrozil were below 1.74 and 1.83%, respectively. No chromatographic interferences from the tablet excipients were found. The results of the developed procedure in tablets were compared with those of the reference method to assess gemfibrozil content. Statistical comparison of the results with the reference method using spectrofluorimetric method showed excellent agreement and proved no significant difference in accuracy and precision. This HPLC method is fast and simple for the analysis of gemfibrozil in pharmaceutical preparations.     

Cloud-point extraction and reversed-phase high-performance liquid chromatography for the determination of carbamate insecticide residues in fruits

A cloud-point extraction (CPE) method using Triton X-114 non-ionic surfactant was developed for the extraction and preconcentration of carbamate insecticide residues (i.e., methomyl, propoxur, carbofuran, carbaryl, isoprocarb, and promecarb) in fruit samples. The optimum conditions of CPE were 1.5% (w/v) Triton X-114, 7.0% (w/v) NaCl and 20 min equilibrated at 45 °C. The surfactant-rich phase was then analyzed by reversed-phase high-performance liquid chromatography with ultraviolet detection at 270 nm, under gradient separation using methanol and 0.1% (v/v) acetic acid. Under the study conditions, six carbamate insecticides were successfully separated within 27 min. Good reproducibility was obtained with the relative standard deviation of <3% for retention time and <9% for peak area. Limits of detection in the studied fruit samples were in the range of 0.1–1.0 mg kg⁻¹. No carbamate insecticides were detected in the studied fruit samples. The high recoveries of the spiked fruit samples were obtained in the range 80.0–107%. The CPE method has been shown to be a potential useful methodology for the preconcentration of the target analytes, with a preconcentration factor of 14. Moreover, the method is simple, has high sensitivity, consumes much less solvent than traditional methods, and is environmental friendly.     

Determination and Pharmacokinetic Study of 10-O-Dimethylaminoethylginkgolide B in Rat Plasma by LC–MS

To evaluate the pharmacokinetics of a novel analogue of ginkgolide B, 10-O-dimethylaminoethylginkgolide B (XQ-1) in rat plasma in pre-clinical studies, a sensitive and specific liquid chromatographic method with electrospray ionization mass spectrometry detection (LC–ESI–MS) was developed and validated. After a simple extraction with ethyl acetate, XQ-1 was analyzed on a Shim-pack C18 column with a mobile phase of a mixture of 1 μmol L⁻¹ ammonium acetate containing 0.02% formic acid and methanol (55:45, v/v) at a flowrate of 0.3 mL min⁻¹. Detection was performed in selected ion monitoring (SIM) mode using target ions at [M + H]⁺ m/z 496.05 for XQ-1 and m/z 432.10 for the internal standard (lafutidine). Linearity was established for the concentration range from 2 to 1,000 ng mL⁻¹ . The extraction recoveries ranged from 86.0 to 89.9% in plasma at concentrations of 5, 50, and 500 ng mL⁻¹. The lower limit of quantification was 2 ng mL⁻¹ with 100 μL plasma. The validated method was successfully applied to a pharmacokinetic study after intragastic administration of XQ-1 mesylate in rats at a dose of 20 mg kg⁻¹.     

Validation of a new planar chromatographic method for quantification of the heterocyclic aromatic amines most frequently found in meat

A new HPTLC method, in which all the HPTLC steps are performed automatically, has been established for quantification of the five most frequently found heterocyclic aromatic amines (HAA: PhIP, MeIQx, 4,8-DiMeIQx, norharmane, and harmane). The method was used for trace analysis (low μg kg⁻¹ range) of HAA in meat samples and found to be a cost-effective alternative to HPLC, because it enables simultaneous chromatography of up to 20 samples within 30 min. After preconditioning of the HPTLC silica gel layer with ammonia vapour the plate was developed with methanol–chloroform, 1:9 (v/v). At least 4ó separations were obtained and selectivity for the meat matrix was achieved. In repeatability tests relative standard deviations (RSD, n = 14, peak height) were less than or equal to ±3.3%. In tests of intermediate precision (mean value for 14 tracks on six different plates on six different days) RSDs were better than ±2% (peak height). Measurement of the reproducibility of migration distances on six different plates resulted in RSDs less than or equal to ±1.3%. Limits of detection and quantification (S/N 3 and 10, respectively) for the five HAA ranged between 0.4 and 5 ng per band and between 0.8 and 14 ng per band, respectively. With paraffin–n-hexane, 3:7 (v/v), as fluorescence enhancer more sensitive determinations (up to 8.5-fold greater signal intensities) were achieved for PhIP, norharmane, and harmane. In the working range (1:10) polynomial regressions for PhIP, MeIQx, and 4,8-DiMeIQx and linear regressions for norharmane and harmane resulted in RSDs between ±1.9 and 3.6%. To confirm the absence of potentially coeluting minor HAA, rarely formed in meat, mass spectra were occasionally recorded by online ESI–MS. Robustness tests showed that preconditioning with ammonia was essential for successful separation and that relative humidity had only a minor effect on the chromatography. Analysis of HAA in a meat sample by HPTLC/UV-FLD and confirmation of MelQx by MS     

A Validated HPLC Method for Simultaneous Determination of 2-Hydroxy-4-methoxybenzaldehyde and 2-Hydroxy-4-methoxybenzoic Acid in Root Organs of Hemidesmus indicus

A reverse phase HPLC method was developed and validated for the simultaneous determination of 2-hydroxy-4-methoxybenzaldehyde and 2-hydroxy-4-methoxybenzoic acid in the root extracts of Hemidesmus indicus. A comprehensive validation of the method including sensitivity, linearity, reproducibility, accuracy, limit of detection (LOD) and limit of quantification (LOQ) was conducted using the optimized chromatographic conditions. The method was found to be linear (r > 0.998) in the range of 5–350 μg mL⁻¹ for 2-hydroxy-4-methoxybenzaldehyde and for 2-hydroxy-4-methoxybenzoic acid (r > 0.999) in the range 10–300 μg mL⁻¹. The method was found to be precise with inter-day precision values (% RSD) in the ranges of 0.61–1.76% for 2-hydroxy-4-methoxybenzaldehyde and 1.3–2.8% for 2-hydroxy-4-ethoxybenzoic acid while intra-day precisions (% RSD) of two analytes were in the range of 0.41–1.07 and 0.95–2.5%. The limits of detection (LODs) for 2-hydroxy-4-methoxybenzaldehyde and 2-hydroxy-4-methoxybenzoic acid were 0.84 and 2.34 μg mL⁻¹. The described method was fast, sensitive and reproducible, and thus well suited for routine analysis of these two compounds from root extracts of H. indicus and other plants.     

Determination of (E)-3,5,4′-Trimethoxystilbene in Rat Plasma by LC with ESI-MS

(E)-3,5,4′-trimethoxystilbene (BTM-0512) is a resveratrol analog with a variety of pharmacological action, including anti-cancer properties, anti-allergic activity, estrogenic activity, antiangiogenic activity, and vascular-targeting activity against microtubule-destabilization. There is, however, no validated analytical method for quantification of (E)-3,5,4′-trimethoxystilbene in biological matrices, so pharmacokinetic data and suitable methods for determination of the compound in plasma are currently lacking. A rapid and sensitive liquid chromatographic–mass spectrometric method for determination of (E)-3,5,4′-trimethoxystilbene in rat plasma, using carbamazepine as internal standard, has been developed and validated. Plasma samples were treated with acetonitrile to precipitate proteins. Samples were then analyzed by HPLC on a 250mm × 4.6 mm i.d., 5-μm particle, C₁₈ column with methanol–water, 80:20 (v/v), containing 10 mm ammonium acetate and 0.2% formic acid (pH 3.0), as mobile phase, delivered at 0.85 mL min⁻¹. A single-quadrupole mass spectrometer with an electrospray interface operated in selected-ion monitoring mode was used to detect [M + H]⁺ ions at m/z 271.3 for (E)-3,5,4′-trimethoxystilbene and m/z 237.5 for the internal standard. (E)-3,5,4′-trimethoxystilbene and the internal standard eluted as sharp, symmetrical peaks with retention times of 8.9 and 4 min, respectively. Calibration plots for (E)-3,5,4′-trimethoxystilbene in rat plasma at concentrations ranging from 0.01 to 5.0 μg mL⁻¹ were highly linear. Intra-day and inter-day precision, as RSD, was <12.9%, and accuracy was in the range 94.8–104.7%. The limit of detection in plasma was 0.005 μg mL⁻¹. The method was successfully used to determine the concentration of (E)-3,5,4′-trimethoxystilbene after oral administration of 86 mg kg⁻¹ of the drug to Sprague–Dawley rats and can be used to investigate the pharmacokinetics of the compound.     

Development and Validation of a Stability-Indicating LC Method for Determination of Ebastine in Tablet and Syrup

A simple stability-indicating reversed-phase liquid chromatographic method with diode-array detection was developed and validated for the quantitative determination of ebastine in tablets and syrup. The LC method was carried out on a C₁₈ column with acetonitrile:phosphoric acid 0.1% pH 3.0 (55:45, v/v) as mobile phase, at a flow rate of 1.2 mL min⁻¹. Ultraviolet detection of ebastine was at 254 nm. A linear response (r = 0.9999) was observed in the range of 10–80 μg mL⁻¹. The RSD values for intra- and inter-day precision studies showed good results (RSD < 2%) and accuracy was greater than 98%. Validation parameters such as specificity and robustness were also determined. The method was found to be stability-indicating and can be applied to quantitative determination of ebastine in tablets and syrup.

     

An LC method for monitoring medium-chain fatty acid permeation through CaCo-2 cell monolayers

A simple method was developed for monitoring the permeation of medium-chain fatty acids of C8 (octanoic acid) and C10 (decanoic acid) through CaCo-2 cell monolayers by high-performance liquid chromatography with electrochemical detection (HPLC-ECD). The detection was made based on the electrochemical reduction prepeak of quinone caused by acids, requiring the fabrication of a two-channel HPLC-ECD system. In one channel, acetonitrile–water (7:3, v/v) was used as a mobile phase to separate acids by a C30 column. In the other channel, acetonitrile–water (7:3, v/v) containing 6 mmol/L 3,5-di-t-butyl-1,2-benzoquinone and 20 mmol/L LiClO₄ was used as a quinone solution to detect acids by an electrochemical cell with a glassy carbon working electrode. In this HPLC-ECD system, eluted acids were mixed with the quinone solution in a post column fashion to obtain current signals caused by acids. The peak area was found to be linearly related to the acid amount ranging from 25 to 1,000 pmol (r > 0.992). The detection limits of octanoic acid and decanoic acid were 7.5 and 8.8 pmol, respectively. Octanoic acid and decanoic acid spiked into cell culture media samples were extracted with acetonitrile and their recoveries were more than 89.5% with an RSD of less than 8.2%. This method was applied to the permeation experiment of octanoic acid and decanoic acid with CaCo-2 cell monolayers formed on the Transwell? system. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. This work was partly presented at The Physical Pharma Forum 2008 on March 24, 2008 in Tokyo, Japan.     

LC Method for Determination of Ginkgolic Acids in Mice Plasma and Its Application to a Pharmacokinetic Study

A sensitive and simple LC method for the quantification of ginkgolic acids in mice plasma has been developed. Following acetonitrile deproteinization, samples were separated on a SinoChrom ODS-AP C₁₈ column. The mobile phase was 3% (v/v) acetic acid water solution–methanol (8:92, v/v) at a flow rate of 1.0 mL min⁻¹. Detection was at 310 nm. Calibration curve was linear over the range of 0.25–50 μg mL⁻¹ with intra- and inter-day precisions (RSD%) of less than 9.5%. The extraction recovery ranged from 87.0 to 90.2% (RSD 2.4–6.4%) for ginkgolic acids. The method was successfully applied to the pharmacokinetic study of ginkgolic acids in mice after oral dosing of 1.0 g kg⁻¹.